Sal@Evolve mentioned that the XPipe can be produced with or without cats and resonators.

He also mentioned that all those dynos were completed with no modified tune.

Looking at the data that Evolve collected, you'll notice that there really isn't any loss in power by retaining high flow secondary cats. I am assuming that is one reason why they decided to keep it. This gives the client the opportunity to still pass emissions with a proper tune, which Evolve also mentioned.

Thanks.
I mustve missed all those points somewhere lol

And I thought the debate of power loss was valves open vs closed. Not cat vs catless. I see they dynoed oem cats vs their own x pipe with no measurable power loss but non with catless?